Since early human history, scents and fragrances have been used to modify body odor. They were obtained in raw form such as resins, gums or essential oils and derived from natural sources, such as the bark, roots, leaves and fruit of indigenous plants and trees. These raw materials were then diluted with water or other solvents and applied to the skin. In modern times, the chemical components responsible for the odor properties of these raw materials were isolated and identified. Current day perfumery engages in combining various fragrance materials to obtain novel fragrance compositions with specific “characteristics”.
In light of the advancements in chemical technology many fragrances are no longer derived from natural sources but are synthesized as highly pure fragrance raw materials (FRM). Furthermore, fragrances have been categorized into three “note” types based on their relative volatility; base, having the most long lasting aroma; middle having a medium volatility, and top notes being the most volatile. If used correctly the different note combinations can produce a “balanced fragrance” composition i.e. one which diffuses in a manner having an aesthetic pleasing effect.
In addition, fragrances have been grouped according to the odor they produce, by using both broad and specific descriptions. For example, “floral” is a term used for odors associated with flowers while the term “lilac” is more specific. Additional examples of descriptive terms include “rose”, “floral”, “green”, “citrus”, “spicy”, “honey”, and “musk”.
Due to an uneven evaporation rate of the different components, the initial fragrance may be quite different from the aroma perceived several hours later. Several methods have been commonly employed to address this issue. One method is to “load up” on the perfume initially and rely on the natural evaporation rate to diminish the fragrance so as to reach a suitable level several hours later when the desired effect is required. Another method is to continually reapply small amounts of the perfume to the skin at short time intervals. However neither of these solutions overcomes the problem of the diminishing level of top and middle notes over time. In fact, base notes which are present over an extended period in light of their low volatility, begin to accumulate with each renewed appliance of perfume, with the possible outcome of overwhelming the other fragrance notes and negating the original fragrance balance.
Acrylic acid (prop-2-enoic acid) is an organic compound with the formula CH2═CHCO2H. It consists of a vinyl group connected directly to a carboxylic acid terminus and is the simplest unsaturated carboxylic acid. It is a colorless liquid with an acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. It is used extensively in different forms and more than one billion kilograms are produced annually. Acrylic acid is produced from propene which is a byproduct of ethylene and gasoline production.
Acrylate polymers belong to a group of polymers which are commonly referred to as plastics. Some of their notable characteristics include transparency, resistance to breakage, and elasticity. They are also generally known as acrylics or polyacrylates. Acrylate polymers are formed from Acrylate monomers which are based on the structure of acrylic acid or are derivatives of acrylic acid, such as methyl methacrylate in which one vinyl hydrogen and the carboxylic acid hydrogen are both replaced by methyl groups, and acrylonitrile in which the carboxylic acid group is replaced by the related nitrile group.
Acrylic paint is a paint containing a pigment suspension in an acrylic polymer emulsion. It can be diluted with water, but becomes water-resistant when dry. Depending on the degree to which the paint is diluted with water, or modified with acrylic gels, media, or pastes, the finished acrylic painting can have unique characteristics not attainable with other media.